Stable Isotope and trace element analyses (Ca, Sr, Mg, Fe and Mn concentrations) derived from Cretaceous Belemnites including Duvalia tornajoensis, D. cf. lata constricta, D. binervia, D. cf. emericii, Hibolithes, H. cf. jaculoides, Berriasibelus, Castellanibelus and Pseudobelus.